Optimal product blending and component inventory management is a complex and vital process that can ultimately define the profitability of a refining operation. Today, the objective of the product blending operations in a refinery is to meet all the shipment commitments on schedule, while operating within the tank inventory constraints both for the blending components as well as the blended products. In addition, this operation should be executed in an optimal fashion in terms of overall cost and profitability. An example of product blending operations in a refinery is shown in FIG. 1. A multi-period blending optimization system (e.g., Aspen MBO v. 6.6.39 in aspenOne v. 7.3 by assignee Aspen Technologies, Inc., Burlington, Mass.) has been developed that provides a detailed representation of the entire blending operation of a refinery complex. That historical Aspen MBO incorporates multiple blend headers and multiple blends in a multi-period event-driven campaign, using open-equation based optimization and modeling technology to produce the optimum schedule for multi-period blending, along with optimum recipes and blended volume for each blend, while addressing the underlying inventory optimization problem. In addition, historical Aspen MBO optimizes all facets of the production blending operations including all external component and product receipts and shipments, as well as relevant intra-refinery transfers.
Traditionally, the goal of blending operations has been to meet product demand and specifications and only as a by-product to minimize give-away losses, that is, losses that occur when premium quality product must be sold for the regular product price. Over the last decade, however, advances in modeling and optimization technology have enabled the deployment of complex nonlinear optimization modeling technologies to address this problem.
The objective of product blending operations in a refinery is to meet all the shipment commitments on schedule, while meeting all the quality specifications. At the same time, the entire blending operation needs to be within all tank inventory minimum and maximum constraints both for the blending components as well as for the blended products, for the predetermined campaign horizon. In addition, this entire operation should be executed in an optimal fashion in terms of both cost and quality giveaway by utilizing the least expensive components over the existing schedule time frame. In this way, the most valuable components can be better utilized in higher quality products or as direct sales, thus increasing the net profitability of the refinery. Even in cases where there is no room for producing more high-priced products and there is no opportunity for high-value component sales, benefits can be realized by reducing the operating cost of the refinery by lowering the demand on units that produce high-value components.
Multi-period blending optimization, however, was not designed to optimize blending operations for components without storage tanks, while some refineries, such as refineries in Eastern Europe, have such operations. Therefore, there is a need for a multi-period blending optimization system that can optimize blending operations for components without storage tanks